J. S. Bach wrote these piano studies, Inventions & Sinfonias, between 1720 and 1723 to help instruct his son in the playing and handling of 2- and 3-part pieces. There are as many interpretations as there are pianists, as one can conclude by those recorded. Glenn Gould has even rearranged the order, mixing the 2 and 3 parts alternately. Mr. Robbins selected a dozen of all the pieces for this ballet.